Conveyor for used toner in a cleaning device of an electrographic printer or copier

ABSTRACT

A printer or copier has an intermediate carrier for applying toner to the recording medium. Used toner is scraped off the intermediate carrier and carried away by a conveyor helix. The conveyor helix is of a spring wire and a resistance element is provided extending between coils of the conveyor helix to intermittently catch and release the spring wire so as to cause wobbling of the conveyor helix and prevent sticking of the used toner.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to a conveyor means for used toner ina cleaning mechanism of an electrographic printer or copier device.

2. Description of the Related Art

A cleaning mechanism is allocated to the printer or copier device forthe removal of toner residues and other particles from the surface of anintermediate carrier, particularly a photoconductor drum. Particlesadhering to the intermediate carrier are removed using a stripperelement lying against the intermediate carrier.

Such a cleaning mechanism is disclosed by European Patent Document EP-04640 032 B1. The known cleaning mechanism contains a stripper elementextending over the width of the intermediate carrier. This stripperelements scrapes off toner residues and contaminants adhering to thesurface of the intermediate carrier. These residues drop into a troughfrom which they are conveyed out. The trough partially surrounds aconveyor worm that is coupled to a drivable shaft via a claw coupling.The conveyor worm is preferably fabricated of resilient material suchas, for example, a spring wire. The used toner is conveyed out of thecleaning station by rotation of the conveyor worm.

It has now been shown that the pourability and flowability of the usedtoner decreases dependent on the temperature, particularly givenemployment of developer material that is suitable for high print imageresolutions. In the extreme case, this leads to the used tonercollecting in the trough of the cleaning station and no longerproceeding into the area of influence of the conveyor worm, which leadsto a tunnel formation of toner. In this case, the elimination of theused toner is no longer assured.

SUMMARY OF THE INVENTION

The present invention is based on the object of providing a conveyormeans for used toner in a cleaning mechanism of an electrographicprinter or copier device that assures that the used toner will bereliably conveyed out of the cleaning station even given used tonerhaving deteriorated flowability and pourability.

This and other objects and advantages of the invention are achieved by acleaning mechanism for an electrographic printer or copier device,wherein the cleaning mechanism contains: a stripper element that stripsused toner from the surface of an intermediate carrier of theprinter-copier device, a trough for catching the stripped-off usedtoner, a conveyor helix of spring wire partially surrounded by thetrough of the cleaning mechanism that rotates around a drive shaftduring operation, and a resistance element for acting on the conveyorhelix such that the conveyor helix is periodically compressed andreleased in a pulse-like manner. Developments and improvements of theinvention are provided when the resistance element a spring hook thathas its free end penetrating between two turns of the conveyor helixinto the interior thereof and has its other end stationarily seatedrelative to the conveying direction of the conveyor helix. In apreferred embodiment, a spacing is provided between conveyor the helixand the trough that is of such a size that a wobbling motion of theconveyor helix as a result of the resistance element is assured.

Due to the means for producing a pulsed motion of the conveyor worm, theused toner proceeds reliably into the area of influence of the conveyormeans. As a result thereof, a reliable elimination of the used toner isassured even given reduced flow and pouring behavior. Contamination ofthe printer or copier device due to uncontrolled emergence of the usedtoner from the cleaning station can be effectively prevented. Damage toor destruction of the intermediate carrier due to collected, used tonerin the cleaning station cannot occur.

BRIEF DESCRIPTION OF THE DRAWINGS

An example of the invention is explained in greater detail below withreference to the drawing.

FIG. 1 is a schematic sectional view of the present invention with aview with photoconductor drum and a cleaning station; and

FIG. 2 is a front view of an inventive conveyor means of the cleaningstation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIG. 1, a photoconductor drum FLT of a printer or copierrotates in a clockwise direction. A cleaning station that extends in anaxial direction of the photoconductor drum FLT over the entire widththereof is arranged at the circumference of the photoconductor drum FLT.

The cleaning station RS contains a stripper element BL. A ledge with arectangular crossection that extends over the entire width of thephotoconductor FLT serves as the stripper element BL. The stripperelement BL has one edge lying on the surface of the photoconductor drumFLT, so that toner particles located on the surface of thephotoconductor drum FLT are scraped off by the stripper element BL uponrotation of the photoconductor drum FLT.

The particles that are scrapped off are a matter of a mixture of toner,paper fibers and other contaminants that are referred to below as usedtoner TO. The used toner which has been stripped off of thephotoconductor drum FLT falls into a receptacle trough WN of thecleaning station RS under the force of gravity and is collected therein.In order to prevent a contamination of the environment of the cleaningstation RS, a seal strip SBL that covers the gap between the cleaningstation RS and the surface of the photoconductor drum FLT is arrangedbetween the trough WN and the surface of the photoconductor drum FLT,whereby this seal strip SBL slides on the surface of the photoconductordrum FLT.

A conveyor helix F whose ends are coupled to a drive shaft FA isarranged in the trough WN of a the cleaning station RS. The conveyorhelix F is composed of a spring wire. The drive shaft FA forms therotational axis of the conveyor helix F surrounded by the trough WN. Aspacing that allows a tumbling motion of the conveyor helix Ftransversely relative to the axial direction is provided between theconveyor helix F and the inside wall of the trough WN.

With the conveyor helix F, the used toner TO is conveyed out of thecleaning station RS into a collecting vessel shown schematically, beingconveyed in a direction that is dependent on the winding direction ofthe conveyor helix F and on the rotational sense of the drive shaft FA.

A spring hook FH penetrates between two turns of the conveyor helix Finto the interior thereof along the longitudinal extent of the conveyorhelix F. With respect to the conveying direction of the conveyor helixF, that end of the spring hook FH facing away from the conveyor helix Fis stationarily coupled to the housing of the cleaning station RS.

Given a rotation of the conveyor helix F, the spring hook FH isdeflected in the conveying direction and is pressed out of the interiorof the conveyor helix F. As viewed in the conveying direction, theconveyor helix F is thereby compressed preceding the spring hook FH andstretched following the spring hook FH. Over and above this, theconveyor helix F is deflected transversely relative to the axialdirection. This pre-stress of the spring helix F is compensated in apulse-like manner when the spring hook FH jumps over the turn of theconveyor helix F against which it is pressed. Given the pulse-likerelease of the conveyor helix F, the spring is excited to oscillate inan axial direction, and a wobbling motion around the drive shaft FA issuperimposed thereon. Used toner TO that could collect in the gapbetween conveyor helix F and trough WN is thereby seized by the conveyorhelix F and carried off. A collection of used toner TO is thus alreadyprevented at the outset thereof.

Although other modifications and changes may be suggested by thoseskilled in the art, it is the intention of the inventors to embodywithin the patent warranted hereon all changes and modifications asreasonably and properly come within the scope of their contribution tothe art.

We claim:
 1. A cleaning mechanism for an electrographic printer or copier device having an intermediate carrier for applying toner to a recording medium, comprising:a stripper element mounted to strip used toner from a surface of the intermediate carrier of the printer or copier device, a trough mounted to catch the stripped-off used toner, a drive shaft and a means for rotating the drive shaft; a conveyor helix of spring wire partially surrounded by the trough that rotates around the drive shaft during operation, and a resistance element mounted to act on the conveyor helix such that the conveyor helix is periodically compressed and released pulse-like during rotation.
 2. A cleaning mechanism for an electrographic printer or copier device having an intermediate carrier for applying toner to a recording medium, comprising:a stripper element mounted to strip used toner from a surface of the intermediate carrier of the printer or copier device, a trough mounted to catch the stripped-off used toner, a drive shaft and a means for rotating the drive shaft; a convevor helix of spring wire partially surrounded by the trough that rotates around the drive shaft during operation, and a resistance element mounted to act on the conveyor helix such that the conveyor helix is periodically compressed and released pulse-like during rotation, said resistance element being a spring hook that has its free end penetrating between two turns of the conveyor helix into an interior thereof and has its other end stationarily seated relative to a conveying direction of the conveyor helix.
 3. A cleaning mechanism according to claim 1, wherein said trough is spaced from said conveyor helix by a spacing of such a size that a wobbling motion of the conveyor helix is assured during rotation of said conveyor helix.
 4. A conveyor for used toner in a cleaning mechanism of an electrographic printer or copier device, the printer or copier device having an intermediate carrier for applying toner onto a recording medium, comprising:a stripper element mounted to strip used toner from a surface of said intermediate carrier, a trough mounted to catch the used toner that is stripped by said stripper element, a drive shaft and a means for driving the drive shaft, a conveyor helix partially surrounded by said trough that rotates around said drive shaft, and a resistance element mounted to act on the conveyor helix such that the conveyor helix is periodically compressed and released pulse-like as said conveyor helix rotates.
 5. A conveyor for used toner in a cleaning mechanism of an electropgraphic printer or copier device, the printer or copier device having an intermediate carrier for applying toner onto a recording medium, comprising:a stripper element mounted to strip used toner from a surface of said intermediate carrier, a trough mounted to catch the used toner that is stripped by said stripper element, a drive shaft and a means for driving the drive shaft, a conveyor helix partially surrounded by said trough that rotates around said drive shaft, and a resistance element mounted to act on the conveyor helix such that the conveyor helix is periodically compressed and released pulse-like as said conveyor helix rotates, said resistance element being a spring hook that has its free end penetrating between two turns of said conveyor helix into an interior thereof and has its other end stationarily seated relative to a conveying direction of the conveyor helix.
 6. A conveyor as claimed in claim 4, wherein said conveyor helix and said trough are spaced apart by a spacing that is of such a size that said conveyor helix undergoes a wobbling motion within said trough. 